Dental implement



Se t. 10, 1935. E. A. PAGE DENTAL IMPLEMENT Filed Sept. 11, 1954Patented Sept. 10, 1935 UNITED STATES PATENT OFFIQE 8 Claims.

This invention relates to dental implements and has for its object toprovide an implement desiged for insuring the correct location of theteeth in artificial dentures.

In the making of dentures, and particularly in the manufacture of lowerdentures or dental plates, it is generally recognized by the professionthat the teeth, with the exception of the frontal teeth, should occupy aposition directly above the alveolar ridge of the jawbone upon which thedenture is to be supported in the mouth. This is because anymisplacement of the teeth, either to one side or the other of thisridge, results in a tendency when the denture is in use to unbalance it.And this is especially true when the teeth are disposed outside orforwardly of the ridge, which condition permits the denture to rock uponthe gums when the teeth are employed in chewing to break the suctionbetween gums and denture that normally retains the latter in place.

While this principle of prosthetic dentistry is generally respected bythe dental profession, considerable expertness is called for in thecorrect articulation of the teeth by the methods of denture making nowcommonly practiced. According to these methods, after the wax base platehas been formed from the plaster of Paris model conforming to thecontour of the gums of the patient being fitted, the teeth are insertedin the plastic waX one by one preparatory to the step of molding thefinal denture therefrom. In this tooth-setting operation the dentistdepends largely upon guesswork in determining the line upon thetooth-sustaining side of the base plate that corresponds to the alveolarridge. And because the contour of the base plate upon itstooth-sustaining surface seldom conforms precisely to the contour of thegums, quite often a dentist will be misled into believing he is locatinga tooth directly over the bottom of the recess corresponding to theridge of the gums when, as a matter of fact, this is not true.

Similarly, the frontal teeth, and more particularly the incisors, shouldpreserve a definite relationship with respect to the alveolar ridge.That is, they should occupy a position just forwardly or outside of theridge of the jaw and incline slightly inwardly toward the back of themouth. The correct placement of these teeth in the base plate likewisecalls for considerable skill on the part of the dentist.

It is an important object of the present invention to facilitate denturemaking and to eliminate to a large extent the element of chance which isinvolved in the placement of the teeth according to the practices now invogue. More especially the invention aims to provide an implementdesigned for checking the location of the teeth at'the time they aremounted in the wax base plate in order to insure their correct positionwith respect to the alveolar ridge in the finished denture. To this end,the invention contemplates the provision of an implement having a finderadapted to be introduced into the gum-engaging recess upon the underside of a base plate and a gauge located 10 in fixed predeterminedrelationship with respect to the finder and affording a sight fordetermining the correct position of a tooth embedded within the uppersurface of the plate.

I prefer to form the gauge with a foot that contacts the crown or cuspsof a tooth and assumes a position centrally thereover when thetoothexcepting one of the frontal teethis properly located in the baseplate, any misalign ment of the tooth being readily ascertained by thedentist by noting the amount of displacement of the tooth off-centerwith respect to the foot.

The implement of my invention is capable of use not only during thepreliminary anchorage of the teeth in the base plate, but is alsohelpful as a fault-finder for checking the teeth of completed denturesthat have proved unsatisfactory in service to determine where theirtrouble lies.

Another object of the invention is to provide a dental implement of theabove character which is of simple construction and which lends itselfto economical manufacture so as to provide an inexpensive tool withineasy reach of any dental worker or student.

Other objects and advantages will be apparent from the followingdetailed description of two preferred embodiments of the implement of myinvention, reference being had to the annexed sheet of drawings inwhich:

Figure 1 is a view of a dental implement in side elevation shown inposition for checking a molar located in a base plate forming thepattern for a lower denture, the base plate being illustrated incross-section;

Figure 2 is a view in side elevation of one end of a slightly modifiedform of implement and indicating its position of use for checking theplacement of an incisor;

Figure 3 is a view in perspective of the dental implement of Fig. 2; and

Figure 4 is a cross-sectional View of the dental implement of Fig. 2taken along the line 44 of that figure.

The dental implement shown in Fig. 1 comprises a pair ofarms l and 2made of light sheet metal stock pivotally connected at one end by a pin3. These arms are of suflicient length to afford convenient grips sothat the two arms may be clasped in one hand of the operator during useand their opening and closing movement readily controlled. The oppositelongitudinal edges of the arms desirably are folded over as indicated at4 and 5 to eliminate the sharp corners which otherwise would bepresented to the hand.

Intermediate the end of arm I, which I term the upper arm, is adepending leg 6 adapted to slide in face-to-face contact with acompanion leg 'I constituting an upwardly disposed section of the arm 2,which latter arm I term the lower arm. The leg 1 is provided with an ear8 integral with the leg and bent over the outer face of the leg 5 toprevent spreading of the arms out of parallelism but permitting theirpivotal movement about the pin 3.

In order to limit the pivotal movement of the arms, I provide a check 9constituting a step upon the leg 5 which rides into engagement with theear 8 when the arms are opened. Formed within the leg I in alignmentwith the leg 6 is a longitudinal slot I0, and extending through thisslot is a screw II carrying a dog I2 which may be adjusted lengthwise ofthe slot and retained in position by tightening the screw within a nut,not shown, located upon the opposite side of the arm from the dog I2.The dog thus serves as a stop for the lower end of the leg 6 when thearms are closed together.

The upper arm I is longitudinally extended beyond the leg 6 to form aguide I3 provided with a straight-edge I4. This guide supports arectangular-shaped gauge I5 disposed perpendicularly with respect to thestraight-edge. The gauge is made of a strip of thin metal bent uponitself to slidingly embrace opposite faces of the arm I. One face of thegauge is recessed to provide a pair of vertically aligned slots I6 andI! which receive within them tongues I8 and I9 bent outwardly from theface of the upper arm, the arrangement being such that the gauge iscapable of sliding movement, guided by the tongues I8 and I9 and to theextent permitted by the slots, in a direction perpendicular to thestraight-edge I4. The lower end of the gauge terminates in a foot I5aadapted to contact the crown of a tooth fastened in a base plate D. Thisfoot is of a width approximately equal to that of a molar and is definedby a fiat toothcontacting lower end and parallel side edges I5b and I50,which latter edges in the use of the implement constitute referencemeans for determining the correct location of a tooth.

The free end of the lower arm 2 is fashioned so as to describe a hook 20terminating in an upright finger 2I defining a finder having a ballpoint 22 mounted upon its upper end. The finder ill is slightly bent todispose the ball point 22 in the plane of the upper arm and this ballpoint is located in alignment with the gauge I5 so that an extension ofthe longitudinal median line of the gauge includes a radius of the ballpoint. In general the dog I2 will be so adjusted within the slot II)that the two arms I and 2 will be approximately parallel when closedtogether and the ball point 22 spaced about onehalf inch from thestraight-edge I4. The hook is designed to permit the introduction of theball point into the bottom of the gum-engaging recess of the denture Dwhile affording sufficient clearance for the walls of the recess.

The construction of the modified form of implement illustrated in Figs.2 to 4, inclusive, is substantially the same as that shown in Fig. 1,just described. Consequently the same reference numerals are employed todesignate corresponding elements of the implements of these figures.

The implement of the latter figures differs from the implement of Fig. 1only by the provision of a sliding mounting for the ball point 22. Asbest illustrated in the cross-sectional view of Fig. 4, the ball pointis mounted upon the end of a pair of parallel arms 30 and SI straddlingthe upright finger constituting finder ii. The finder is provided withtwo elongated slots 32 disposed in alignment and extending in thedirection of the length of the finder. Transverse pins 33 and 33a passthrough the arms 30 and SI and through the slots 32, the arrangementbeing such that the pins sliding within the slots serve to guide theball point 22 in a straight line coinciding with the extended medianline of the gauge I5.

The ball point 22 is normally held in its raised position with the pins33 and 33a engaging the upper ends of their respective slots under theurge of a spring 34. The spring 34 is formed to engage the hook 213 andhas its two free ends passed below extensions of the pin 33a projectingfrom opposite sides of the hook. In order to impart tension to thespring, intermediate sections thereof are coiled about the shank of acylindrical lug 35 drive-fitted within an opening formed in the hook,the lug having its ends extended beyond opposite faces of the hook andsuitably headed to retain the spring coils in place thereon.

The manner in which both forms of the implement described above are usedis substantially the same: All the teeth having been positioned in thewax base plate according to the best judgment of the dentist, the teethare checked prior to introducing the base plate into a mold to form thematrix from which the final denture is cast. Care in locating the teethin the base plate is necessary for the reason that any error in thealignment of the teeth in the base plate will be carried over into thefinished denture.

The dentist grasps the arms I and 2 of the implement in one hand andwith his other hand supports the base plate D in a horizontal planeabout on the level with his eyes, sighting from the rear toward thefront of the plate. Starting with the rear molars, the dentist separatesthe two arms I and 2 of the implement to the maximum extent permitted bythe check 9 and ear 8 and inserts (11 the ball point 22 of the finder 2|into the bottom of the recess upon the under side of the base plate, atthe same time seeing to it that the guide I3 is positioned over thecorresponding molar upon the distant margin of the plate.

The arms are then closed which causes the straight-edge I4 to rest uponthe two molars, the foot I5a of gauge I5 upon riding into contact withthe molar under which the ball point 2I has been positioned beingprojected vertically upward into the position shown in Fig. 1. Thedentist now notes the displacement, if any, of the molar contacted bythe foot Ifia with respect to the parallel edges I51) and IE0 of thegauge.

If the molar is centrally located with respect to the foo-t, then thedentist knows that this molar, when transferred to the completeddenture, will lie directly above the jaw bone. This follows from thefact that the bottormnost portion of the recess contacted by the finder,that is, the ball point 22, corresponds to the crest of the gumscovering the jaw bone, and this point is in this way automaticallytransferred from the lower to the upper side of the base plate by thegauge l5 by virtue of the fact that the gauge is disposed in exactalignment with the ball point of the finder. If, on the other hand, themolar is found to be out of alignment with the foot I5a, then thisinforms the dentist that the molar requires resetting before proceedingto the next step in the manufacture of the denture.

In the same way the remainder of the teeth may be checked. In checkingthe incisors, however, the guide |3 will extend diagonally or endwisewith respect to the base plate as shown in Fig. 2, and care isexercised, in order to avoid error in taking an observation from thegauge, to see that the implement is held so that the straight edge l4extends in a plane generally parallel with the crest line of the teeth.The gauge [5 being slidable will accommodate itself to teeth ofdifferent heights without spreading the arms I and 2, these latter beingactuated only upon introducing the ball point into and removing it fromthe gum-engaging recess.

The rearwardly inclined incisors, however, instead of engaging the footI 5a centrally when in their correct position of placement will, on thecontrary, contact the foot about th or %ds of an inch inwardly from theside I50, as shown in Fig. 2. Of course the above mode of use of myimproved dental implement is simply suggestive, and the dentist willdoubtless develop his own technique as he becomes familiar with thedevice.

In the use of the modified form of implement provided with a slidableball point 22, the spring 34 serves to automatically urge the ball intothe lowermost depth of the gum-engaging recess when the finder isintroduced into this recess.

While the dental implement of my invention has been described above inconnection with a base plate used in forming a lower denture, theinvention is not so limited and may be used to good advantage indetermining the correct position of the teeth in base plates for upperdentures. Furthermore, as has previously been pointed out, the implementof the invention finds additional utility in checking the teeth ofcompleted dentures to discover their imperfections. The term dentalplate as used in the appended claims is employed in a broad sense toinclude the base plates made of plastic material in an intermediate stepin the process of denture making, as well as dentures in either theircompleted or uncompleted state. By the term ball point is meant anyspherical or dome-shaped element upon the end of finder 2| which easilyslides upon the walls of the gum-engaging recess and seeks its deepestportion.

It will be obvious that many changes in arrangement and design may bemade in the structure of the dental implements described above withoutdeparting from the spirit of my invention.

I claim:

1. An implement for checking the location of teeth on dental platescomprising a finder adapted to be inserted in the gum-engaging recess onthe under side of a dental plate, the finder comprising an uprightfinger terminating in a ball point designed to contact substantially thedeepest portions of the recess, an elongated gauge, having a fiattooth-contacting foot of approximately the width of a molar, a supportfor the gauge, the gauge being disposed perpendicular to the supportandin alignment with the ball point, means connecting the gauge and thefinder to permit relative movement of the gauge and finder toward andfrom each other.

2. An implement for checking the location of teeth on dental platescomprising a finder adapted to be inserted in the gum-engaging recess onthe under side of a dental plate, the finder comprising an uprightfinger terminating in a ball point designed to contact substantially thedeepest portions of the recess, an elongated gauge having a flattooth-contacting foot of approximately the width of a molar so as toengage opposite cusps of a tooth, a support for the gauge, the gaugebeing disposed perpendicular to the support and in alignment with theball point, and means connecting the gauge and the finder to permitrelative movement of the gauge and finder toward and from each other,said gauge having parallel sides adjacent its tooth-contacting footproviding reference means for centering a tooth with respect to thebottom of the gumengaging recess.

3. An implement for checking the location of teeth in dental platescomprising a finder adapted to be inserted in the gum-engaging recess onthe under side of a dental plate, the finder comprising an uprightfinger terminating in a ball point designed to contact substantially thedeepest portions of the recess, an elongated gauge having a fiattooth-contacting foot of approximately the width of a molar so as toengage opposite cusps of a tooth, a support for the gauge,

the gauge being disposed perpendicular to the support and in alignmentwith the ball point, means connecting the gauge and the finder to permitrelative movement of the gauge and finder toward and from each other,and a guide upon said gauge support forming an extension of said supportbeyond the gauge and having a straightedge at right angles thereto, saidguide being of a length approximately equal to the distance betweencorresponding molars upon opposite sides of the dental plate.

4. An implement for checking the location of teeth on dental platescomprising a finder adapted to be inserted in the gum-engaging recessupon the under side of a dental plate, the finder comprising an uprightfinger terminating in a ball point designed to contact substantially thedeepest portions of the recess, a gauge, means supporting the gaugeabove the upper side of the denture in predetermined alignment withrespect to the finder, the finder and gauge-supporting means beingconnected for relative movement toward and from each other and the gaugebeing independently slidable on its supporting means toward and from thefinder, a flat tooth-contacting foot upon the gauge of sufiicient extentto engage the opposite cusps of a tooth and thereby position the gauge,and reference means on the gauge to permit of the visual determinationof the position of a tooth with respect to the recess.

5. An implement for checking the location of teeth on dental platescomprising a finder adapted to be inserted in the gum-engaging recess onthe under side of a dental plate, the finder comprising an uprightfinger terminating in a ball point, designed to contact substantiallythe deepest portions of the recess, an elongated gauge, a support forthe gauge, the gauge being disposed perpendicular to the support and inalignment with the ball point, and means connecting the gauge and thefinder to permit relative movement of the gauge and finder toward andfrom each other, means slidably connecting the ball point to the fingerfor movement toward and from the gauge, and resilient means biasing theball point toward the gauge.

6. An implement as described in claim 1 in which the support for thegauge and the means connecting the gauge and finder comprise relativelylong arms pivotally connected together.

7. An implement as described in claim 1 in which the support for thegauge and the means connecting the gauge and finder comprise relativelylong arms formed of sheet material pivotally connected together at oneend in superposed relation.

8. An implement as described in claim 1 in which the support for thegauge and the means connecting the gauge and finder comprise relativelylong arms formed of sheet material pivotally connected together at oneend in superposed relation and having means for limiting the pivotalmovement of said arms.

ERNEST A. PAGE.

